When u fit them warm them up before you clip them on, otherwise they may well split
yep, definitely do that, particularly in this weather. first rivet them to the side skirt, and then use a hot air gun or hair dryer to warm up the clip bit before clipping them onto the sill seam. otherwise when you go to clip them on, the clip will break in half and you'll say 'bugger, that's 3 quid down the drain'